Premium
EFFECTS OF METABOLIC INHIBITORS ON THE RELEASE OF GLUTAMATE FROM THE RETINA 1
Author(s) -
Harreveld A. Van,
Fifkova Eva
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb05087.x
Subject(s) - glutamate receptor , extracellular , biophysics , intracellular , stimulation , chemistry , biochemistry , glycolysis , metabolism , biology , microbiology and biotechnology , endocrinology , receptor
—The superfused, isolated retina of the chicken was used to investigate the mechanisms responsible for the increase in retinal transparency and the release of glutamate associated with stimuli known to elicit spreading depression (SD). We sought to distinguish between (1) mechanisms involving glutamate‐induced increase in Na + permeability and consequent uptake of extracellular material into the intracellular compartment and (2) mechanisms involving interference with operation of the Na + pump that would result in a similar uptake of extracellular materials. Tetrodotoxin (which inhibits inward movements of Na + ) depressed the transparency increase caused by stimulation with glutamate but not that elicited by application of KCl. Ouabain (which inhibits the Na + pump) caused a marked increase in tissue transparency. The application of inhibitors of the aerobic metabolism, such as DNP or cyanide, or deprivation of O 2 had no effect on the retinal transparency; results suggesting that the energy for the Na + pump could be supplied by glycolysis. Indeed iodoacetate (which inhibits glycolysis) caused a marked change in transparency. Furthermore we found evidence for a compound in the superfusion fluid supplemented with iodoacetate that may be a reaction product of glutamate and iodoacetate. In some preparations superfusion with glucose‐free solutions caused a slowly developing increase in transparency and release of glutamate; in others the increase in transparency was more sudden and there was a larger release of glutamate. Seemingly, interference with the tissue metabolism can cause an uptake of extracellular material either by arrest of the Na + pump or by the release of glutamate, depending on the conditions of the experiment.